Difference measurement(stays constant with time and depends on distance) 1.00 Outgoing Incoming 0.00 Outgoing + coming+△t 0.4 .8 4 Distance 02/25/02 12.540Lec0602/25/02 12.540 Lec 06 10 Difference measurement (stays constant with time and depends on distance) -1.00 -0.50 0.00 0.50 1.00 0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 Outgoing Incoming Outgoing + ∆t Incoming + ∆t Signal voltage Distance